Turbo Molecular Pump with Improved Blade Structures

ABSTRACT

The present invention discloses a turbo molecular pump with improved blade structures. The turbo molecular pump comprises a rotor and a stator, wherein the rotor includes five rotor blade assemblies and the stator includes five stator blade assemblies, and wherein the blade number and the blade angle of each rotor blade assembly and stator blade assembly are adjusted to optimization, so as to enhance the pumping speed and the stability of the turbo molecular pump as well as to reduce the difficulty for manufacturing the turbo molecular pump.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a turbo molecular pump with improvedblade structures, and more particularly to a turbo molecular pump havingrotor blades and stator blades which are optimally adjusted for severalparameters.

2. Description of the Prior Art

In recent years, semiconductor industries are developed rapidly, so thatthe requirement of the related apparatuses in front-end stage of thesemiconductor is largely increased, and wherein a turbo molecular pump,the major device in the high vacuum system, has a great demand.

The turbo molecular pump is originated in 1912 and improved from amolecular drag pump invented by a German, Gaede. Referring to FIG. 1,which is a cross-sectional view of a conventional turbo molecular pump.The conventional turbo molecular pump A includes a rotor A1 and a statorA2, wherein the rotor A1 includes a rotor shaft A10 and a plurality ofrotor blades A11, and the stator A2 includes a plurality of statorblades A21. The rotor blades A11 and the stator blades A21 are disposedin a staggered manner layer by layer.

Referring to FIG. 2, which is a schematic diagram of an action principleof a turbo molecular pump. After a gas molecule B5 entering the turbomolecular pump B1, the gas molecule B5 get into next level of statorblade B3 driven by a rotor blade B2, as indicated by the dotted line.Following, the gas molecule B5 rams the stator blade B3 and turns itsforward direction, and then gets into the next level of rotor blade B4.Therefore, the action principle of the turbo molecular pump B1 is tomake the gas molecules originally having chaotic movement in the systemmove forward an exit by inclined blades with high-speed rotation, and toelevate a compression ratio by the staggered arrangement of multi-levelrotor blades and stator blades. Owing to the turbo molecular pump hasthe property of high vacuum, high exhaust efficiency and no oilpollution, the turbo molecular pump is widely used on various researchesand applications.

Owing to the turbo molecular pump is popularly applied in researches andindustries with high precision, thus the pumping efficiency is veryimportant. However, although the turbo molecular pump has been improvedby many researchers constantly, the pumping efficiency and the stabilityof the turbo molecular pump are not excellent enough yet.

In view of this, it is necessary to provide an improved turbo molecularpump, which can increase the pumping speed and stability by theoptimized design of the structure.

SUMMARY OF THE INVENTION

In view of the above shortcomings of the prior art, the inventor of thepresent invention resorted to past experience, imagination, andcreativity, performed experiments and researches repeatedly, andeventually devised the present invention, a turbo molecular pump withimproved blade structures.

The major objective of the present invention is to provide the turbomolecular pump with improved blade structures, wherein severalparameters of rotor blades and stator blades of the turbo molecular pumpare adjusted to optimal conditions, so as to significantly elevate thepumping speed and stability of the turbo molecular pump.

According to the above objective, the present invention provides theturbo molecular pump with improved blade structures comprising: a rotorcomprising: a center shaft; a first layered rotor blade assembly beingdisposed on the center shaft, wherein the blade number of the firstlayered rotor blade assembly is 16˜17 pieces, and the blade angle of thefirst layered rotor blade assembly being 37˜45 degree; a second layeredrotor blade assembly being disposed on the center shaft and contiguousto the first layered rotor blade assembly, wherein the blade number ofthe second layered rotor blade assembly is 32˜33 pieces, and the bladeangle of the second layered rotor blade assembly being 45˜50 degree; athird layered rotor blade assembly being disposed on the center shaft,and the third layered rotor blade assembly and the first layered rotorblade assembly being disposed on opposite side of the second layeredrotor blade assembly, wherein the blade number of the third layeredrotor blade assembly is 30˜31 pieces, and the blade angle of the thirdlayered rotor blade assembly being 30˜40 degree; a fourth layered rotorblade assembly being disposed on the center shaft, and the fourthlayered rotor blade assembly and the second layered rotor blade assemblybeing disposed on opposite side of the third layered rotor bladeassembly, wherein the blade number of the fourth layered rotor bladeassembly is 28˜29 pieces, and the blade angle of the fourth layeredrotor blade assembly being 25˜30 degree; a fifth layered rotor bladeassembly being disposed on the center shaft, and the fifth layered rotorblade assembly and the third layered rotor blade assembly being disposedon opposite side of the fourth layered rotor blade assembly, wherein theblade number of the fifth layered rotor blade assembly is 26˜27 pieces,and the blade angle of the fifth layered rotor blade assembly being15˜22 degree; and a stator comprising: a first layered stator bladeassembly being disposed between the first layered rotor blade assemblyand the second layered rotor blade assembly, wherein the blade number ofthe first layered stator blade assembly is 50˜52 pieces, and the bladeangle of the first layered stator blade assembly being 45˜70 degree; asecond layered stator blade assembly being disposed between the secondlayered rotor blade assembly and the third layered rotor blade assembly,wherein the blade number of the second layered stator blade assembly is50˜52 pieces, and the blade angle of the second layered stator bladeassembly being 48˜70 degree; a third layered stator blade assembly beingdisposed between the third layered rotor blade assembly and the fourthlayered rotor blade assembly, wherein the blade number of the thirdlayered stator blade assembly is 50˜52 pieces, and the blade angle ofthe third layered stator blade assembly being 40˜70 degree; a fourthlayered stator blade assembly being disposed between the fourth layeredrotor blade assembly and the fifth layered rotor blade assembly, whereinthe blade number of the fourth layered stator blade assembly is 34˜36pieces, and the blade angle of the fourth layered stator blade assemblybeing 28˜40 degree; and a fifth layered stator blade assembly beingdisposed on opposite side of the fifth layered rotor blade assemblyrelative to the fourth layered stator blade assembly, wherein the bladenumber of the fifth layered stator blade assembly is 34˜36 pieces, andthe blade angle of the fifth layered stator blade assembly being 22˜40degree.

BRIEF DESCRIPTION OF THE DRAWINGS

For a complete understanding of the aspects, structures and techniquesof the invention, reference should be made to the following detaileddescription and accompanying drawings wherein:

FIG. 1 is a cross-sectional view of a conventional turbo molecular pump;

FIG. 2 is a schematic diagram of an action principle of a turbomolecular pump;

FIG. 3 is a perspective view of a rotor of a turbo molecular pump of thepresent invention; and

FIG. 4 is a perspective view of a stator of the turbo molecular pump ofthe present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To achieve the foregoing objectives and effects, the inventors adjustseveral parameters of rotor blades and stator blades of a turbomolecular pump to optimal conditions, thus achieving a turbo molecularpump with improved blade structures.

The turbo molecular pump of the present invention is composed of a rotorand a stator, wherein the rotor and the stator are primarily made ofpure aluminum or aluminum alloy, which has advantages of lightweight,corrosion prevention, manufacturing easily, and moderate strength andtoughness. The rotor and the stator also can be made of copper or gold,however, the copper and the gold have higher cost, softer texture,higher weight, and lower strength and toughness than aluminum.Additionally, steel, iron, cast metal, and stainless steel also can bethe material of the rotor and the stator, but these materials havedisadvantages of rigid texture, heavy weight, susceptible to corrosion,and difficult to be manufactured.

Referring to FIG. 3, which is a perspective view of the rotor of theturbo molecular pump of the present invention. The rotor 100 of thepresent invention includes a center shaft 101, a first layered rotorblade assembly 110, a second layered rotor blade assembly 120, a thirdlayered rotor blade assembly 130, a fourth layered rotor blade assembly140, and a fifth layered rotor blade assembly 150.

The first layered rotor blade assembly 110 is disposed on the centershaft 101. The blade number of the first layered rotor blade assembly110 is 16˜17 pieces, and the blade angle of the first layered rotorblade assembly 110 is 37˜45 degree.

The second layered rotor blade assembly 120 is disposed on the centershaft 101 and contiguous to the first layered rotor blade assembly 110.The blade number of the second layered rotor blade assembly 120 is 32˜33pieces, and the blade angle of the second layered rotor blade assembly120 is 45˜50 degree.

The third layered rotor blade assembly 130 is disposed on the centershaft 101, and the third layered rotor blade assembly 130 and the firstlayered rotor blade assembly 110 are disposed on opposite side of thesecond layered rotor blade assembly 120. The blade number of the thirdlayered rotor blade assembly 130 is 30˜31 pieces, and the blade angle ofthe third layered rotor blade assembly 130 is 30˜40 degree.

The fourth layered rotor blade assembly 140 is disposed on the centershaft 101, and the fourth layered rotor blade assembly 140 and thesecond layered rotor blade assembly 120 are disposed on opposite side ofthe third layered rotor blade assembly 130. The blade number of thefourth layered rotor blade assembly 140 is 28˜29 pieces, and the bladeangle of the fourth layered rotor blade assembly 140 is 25˜30 degree.

The fifth layered rotor blade assembly 150 is disposed on the centershaft 101, and the fifth layered rotor blade assembly 150 and the thirdlayered rotor blade assembly 130 are disposed on opposite side of thefourth layered rotor blade assembly 140. The blade number of the fifthlayered rotor blade assembly 150 is 26˜27 pieces, and the blade angle ofthe fifth layered rotor blade assembly 150 is 15˜22 degree.

Referring to FIG. 4, which is a perspective view of the stator of theturbo molecular pump of the present invention. The stator 200 of thepresent invention includes a first layered stator blade assembly 210, asecond layered stator blade assembly 220, a third layered stator bladeassembly 230, a fourth layered stator blade assembly 240, and a fifthlayered stator blade assembly 250.

The first layered stator blade assembly 210 is disposed between thefirst layered rotor blade assembly 110 and the second layered rotorblade assembly 120. The blade number of the first layered stator bladeassembly 210 is 50˜52 pieces, and the blade angle of the first layeredstator blade assembly 210 is 45˜70 degree.

The second layered stator blade assembly 220 is disposed between thesecond layered rotor blade assembly 120 and the third layered rotorblade assembly 130. The blade number of the second layered stator bladeassembly 220 is 50˜52 pieces, and the blade angle of the second layeredstator blade assembly 220 is 48˜70 degree.

The third layered stator blade assembly 230 is disposed between thethird layered rotor blade assembly 130 and the fourth layered rotorblade assembly 140. The blade number of the third layered stator bladeassembly 230 is 50˜52 pieces, and the blade angle of the third layeredstator blade assembly 230 is 40˜70 degree.

The fourth layered stator blade assembly 240 is disposed between thefourth layered rotor blade assembly 140 and the fifth layered rotorblade assembly 150. The blade number of the fourth layered stator bladeassembly 240 is 34˜36 pieces, and the blade angle of the fourth layeredstator blade assembly 240 is 28˜40 degree.

The fifth layered stator blade assembly 250 is disposed on opposite sideof the fifth layered rotor blade assembly 150 relative to the fourthlayered stator blade assembly 240. The blade number of the fifth layeredstator blade assembly 250 is 34˜36 pieces, and the blade angle of thefifth layered stator blade assembly 250 is 22˜40 degree.

Furthermore, the first layered stator blade assembly 210, the secondlayered stator blade assembly 220, the third layered stator bladeassembly 230, the fourth layered stator blade assembly 240, and thefifth layered stator blade assembly 250 further include a stator shroud211, 221, 231, 241, and 251 respectively, each stator shroud 211, 221,231, 241, and 251 can fasten the blades of each layered stator bladeassembly 210, 220, 230, 240, and 250, and also can used for combiningthe stator blade assemblies 210, 220, 230, 240, and 250 to each other.

In the present invention, the rotor blades and the stator blades of theturbo molecular pump are divided into five layers, which have functionsof increasing the compression ratio and the compression efficiency, soas to achieve the effect of ultrahigh vacuum, and then enhance theaccuracy and the cleanliness of a vacuum coating equipment for asemiconductor process.

By the detailed description of the overall structure and technicalcontent of the present invention, the following advantages of thepresent invention can be derived:

The present invention adjusts several parameters of the rotor blades andthe stator blades to optimal condition, so as to significantly enhancethe pumping speed and the stability of the turbo molecular pump.

The blade number of each layered rotor blade assembly of the presentinvention is less than the blade number of the conventional turbomolecular pump, so that the manufacture and the fabrication of the turbomolecular pump are much easier, and the manufacturing cost can bereduced.

It should be understood that the embodiments of the present inventiondescribed herein are merely illustrative of the technical concepts andfeatures of the present invention and are not meant to limit the scopeof the invention. Those skilled in the art, after reading the presentdisclosure, will know how to practice the invention. Various variationsor modifications can be made without departing from the spirit of theinvention. All such equivalent variations and modifications are intendedto be included within the scope of the invention.

As a result of continued thinking about the invention and modifications,the inventors finally work out the designs of the present invention thathas many advantages as described above. The present invention meets therequirements for an invention patent, and the application for a patentis duly filed accordingly. It is expected that the invention could beexamined at an early date and granted so as to protect the rights of theinventors.

1. A turbo molecular pump with improved blade structures comprising: arotor comprising: a center shaft; a first layered rotor blade assemblybeing disposed on the center shaft, wherein the blade number of thefirst layered rotor blade assembly is 16˜17 pieces, and the blade angleof the first layered rotor blade assembly being 37˜45 degree; a secondlayered rotor blade assembly being disposed on the center shaft andcontiguous to the first layered rotor blade assembly, wherein the bladenumber of the second layered rotor blade assembly is 32˜33 pieces, andthe blade angle of the second layered rotor blade assembly being 45˜50degree; a third layered rotor blade assembly being disposed on thecenter shaft, and the third layered rotor blade assembly and the firstlayered rotor blade assembly being disposed on opposite side of thesecond layered rotor blade assembly, wherein the blade number of thethird layered rotor blade assembly is 30˜31 pieces, and the blade angleof the third layered rotor blade assembly being 30˜40 degree; a fourthlayered rotor blade assembly being disposed on the center shaft, and thefourth layered rotor blade assembly and the second layered rotor bladeassembly being disposed on opposite side of the third layered rotorblade assembly, wherein the blade number of the fourth layered rotorblade assembly is 28˜29 pieces, and the blade angle of the fourthlayered rotor blade assembly being 25˜30 degree; a fifth layered rotorblade assembly being disposed on the center shaft, and the fifth layeredrotor blade assembly and the third layered rotor blade assembly beingdisposed on opposite side of the fourth layered rotor blade assembly,wherein the blade number of the fifth layered rotor blade assembly is26˜27 pieces, and the blade angle of the fifth layered rotor bladeassembly being 15˜22 degree; and a stator comprising: a first layeredstator blade assembly being disposed between the first layered rotorblade assembly and the second layered rotor blade assembly, wherein theblade number of the first layered stator blade assembly is 50˜52 pieces,and the blade angle of the first layered stator blade assembly being45˜70 degree; a second layered stator blade assembly being disposedbetween the second layered rotor blade assembly and the third layeredrotor blade assembly, wherein the blade number of the second layeredstator blade assembly is 50˜52 pieces, and the blade angle of the secondlayered stator blade assembly being 48˜70 degree; a third layered statorblade assembly being disposed between the third layered rotor bladeassembly and the fourth layered rotor blade assembly, wherein the bladenumber of the third layered stator blade assembly is 50˜52 pieces, andthe blade angle of the third layered stator blade assembly being 40˜70degree; a fourth layered stator blade assembly being disposed betweenthe fourth layered rotor blade assembly and the fifth layered rotorblade assembly, wherein the blade number of the fourth layered statorblade assembly is 34˜36 pieces, and the blade angle of the fourthlayered stator blade assembly being 28˜40 degree; and a fifth layeredstator blade assembly being disposed on opposite side of the fifthlayered rotor blade assembly relative to the fourth layered stator bladeassembly, wherein the blade number of the fifth layered stator bladeassembly is 34˜36 pieces, and the blade angle of the fifth layeredstator blade assembly being 22˜40 degree.
 2. The turbo molecular pumpwith improved blade structures according to claim 1, wherein the rotoris made of the material selected from the group consisting of: purealuminum, aluminum alloy, copper, gold, steel, iron, cast metal, andstainless steel.
 3. The turbo molecular pump with improved bladestructures according to claim 1, wherein the stator is made of thematerial selected from the group consisting of: pure aluminum, aluminumalloy, copper, gold, steel, iron, cast metal, and stainless steel. 4.The turbo molecular pump with improved blade structures according toclaim 1, wherein the first layered stator blade assembly, the secondlayered stator blade assembly, the third layered stator blade assembly,the fourth layered stator blade assembly, and the fifth layered statorblade assembly further comprise a stator shroud respectively, eachstator shroud being able to fasten the blades of each layered statorblade assembly, and for combining the stator blade assemblies to eachother.